RESEARCH ON CHEMICAL INTERMEDIATES, cilt.39, sa.7, ss.2979-2987, 2013 (SCI-Expanded)
LiFePO4/C and LiYb0.02Fe0.98PO4/C composite cathode materials were
synthesized by simple solution technique. The samples were characterized by X-ray
diffraction, scanning electron microscope, and thermogravimetric–differential
thermal analysis. Their electrochemical properties were investigated by cyclic
voltammetry, four-point probe conductivity measurements, and galvanostatic
charge and discharge tests. The carbon-coated and Yb3?-doped LiFePO4 sample
exhibited an enhanced electronic conductivity of 1.9 9 10-3 Scm-1, and a specific
discharge capacity of 146 mAhg-1 at 0.1 C. The results suggest that the
improvement of the electrochemical performance can be attributed to the ytterbium
doping, which facilitates the phase transformation between triphylite and heterosite
during cycling, and the conductivity improvement by carbon coating